A sociable drink? (5)
I believe the answer is:
mixer
This clue is a double definition.
'a sociable' is the first definition.
('mixer' can be a synonym of 'sociable')
'drink?' is the second definition.
(mixer is a kind of drink)
(Other definitions for mixer that I've seen before include "Eg, tonic water" , "Soft drink; type of tap" , "Sociable mingler" , "Socialiser" , "Drink to combine with alcohol" .)